Flowing through the heart of the capital, the history of the river Thames offers a powerful symbol for the lives of Londoners through the centuries. In fact, there have been people living on the site since before Roman times, washing there, catching fish and watching the horizon for signs of invaders.
There's a big wedding anniversary on the horizon and I'm in charge of festivities. The wife wants to celebrate the big 10 by doing "something unusual". I can only hope we're on the same wavelength, as I've spent the last few weeks knocking about on the internet looking for wetsuits and picturesque pools in to which we shall be submerged.